Under the Rochester Epidemiologic Program Project (REPP), a unique population-based data resource has been developed comprised of the medical records of all Olmsted County residents for the entire duration of their residency in the county. This centralized records linkage system has served as the basis for over 330 epidemiologic publications on a myriad of topics--many relating to critical health issues of national importance. The research facility has been used not only by Mayo staff, but by many clinical and public health colleagues outside of the Mayo Clinic. The data base consists of the medical records of the Mayo Clinic and other providers whose documented state of the art health care also requires entry of diagnoses of all formal medical encounters into an automated indexing and retrieval system. It is the responsibility of the Rochester Project to collect and collate this information and make it accessible to all investigators for descriptive and analytic studies. These include NIH funded program projects, contracts and other requests from CDC, NIH, and other governmental agencies and personnel as well as the fellowship or small grant supported projects by numerous medical students, epidemiology degree candidates, residents and clinicians from the U.S. and other countries. Continued updating of the central data resource is essential to preserve this research potential. The purpose of this proposal is to maintain and extend the underlying data system. We request funding for: (1) continued supplementation of the Mayo Clinic diagnostic index with data from the Olmsted Medical Group, Olmsted Community Hospital and several other non-Mayo sources of medical care in and around Olmsted County; (2) extending the data base by adding more detailed nursing home information; (3) further development, from the medical records, of an Olmsted County population frame to permit unbiased selection of controls for case-control studies; (4) further development of family linkages within the data base for studies of familial aggregation of disease; (5) efforts to improve the autopsy rate at least back to 70%; (6) initial development of a computerized index to drugs; and (7) continued support for some 45 projects underway including the epidemiology of prostate cancer, psoriasis, amyloidosis, and focal dystonias.